Some of cellular phones are adapted to enable a digital TV broadcast to be watched by including an antenna for receiving a digital TV broadcast wave transmitted from a broadcast base station; displaying TV images on a display screen on the basis of the digital TV broadcast wave; and outputting TV voice corresponding to the TV images.
As an example of this sort of cellular phones, there is one in which a display screen is formed in a rectangular shape, and adapted to be able to be switched between a vertically long display state and a horizontally long display state. That is, in the above vertically long display state, a TV image is displayed with a longer direction of the display screen being made vertical, whereas in the above horizontally long display state, it is displayed with a shorter direction of the display screen being made vertical.
In general, a TV image based on a digital TV broadcast wave transmitted from a broadcast base station has a horizontally long aspect ratio, i.e., a horizontal length is long as compared with a vertical length, and therefore in the horizontally long display state, the TV image can be displayed larger, as compared with the vertically long display state. On the other hand, in the vertically long display state, the TV image is displayed with the horizontal length thereof corresponding to a length of a shorter side of a display screen, and therefore an empty area is created on the display screen, in addition to an area for displaying the TV image. For this reason, this sort of cellular phones includes one that is adapted to be able to effectively use a display area by displaying so-called content data based on a data broadcast in such an empty area on the display screen.
Note that the data broadcast refers to a system in which various types of content data such as news and weather forecast are transmitted separately from the TV image and the TV voice based on the digital TV broadcast wave (e.g., Patent documents 1 and 2). Some of the various types of content data transmitted on the basis of the data broadcast include information associated with a program based on the digital TV broadcast wave in receipt. Accordingly, by displaying the information associated with the program on the display screen as the data broadcast while displaying on the display screen TV images of the program based on the digital TV broadcast wave in receipt, a user can check the associated information with use of the data broadcast while watching a TV broadcast.
Patent document 1: Japanese Unexamined Patent Publication No. 2005-286966
Patent document 2: Japanese Unexamined Patent Publication No. 2005-223649